Replicache

Classes

• IDBNotFoundError
• PullError
• PushError
• Replicache
• TransactionClosedError

Interfaces

• AsyncIterableIteratorToArray
• KVRead
• KVStore
• KVWrite
• LogSink
• ReadTransaction
• ReplicacheOptions
• RequestOptions
• ScanResult
• SubscribeOptions
• WriteTransaction

Type Aliases

ClientGroupID

Ƭ ClientGroupID: string

The ID describing a group of clients. All clients in the same group share a persistent storage (IDB).

---

ClientID

Ƭ ClientID: string

The ID describing a client.

---

ClientStateNotFoundResponse

Ƭ ClientStateNotFoundResponse: Object

In certain scenarios the server can signal that it does not know about the client. For example, the server might have lost all of its state (this might happen during the development of the server).

Type declaration

Name	Type
error	"ClientStateNotFound"

---

Cookie

Ƭ Cookie: null | string | number | ReadonlyJSONValue & { order: number | string }

A cookie is a value that is used to determine the order of snapshots. It needs to be comparable. This can be a string, number or if you want to use a more complex value, you can use an object with an order property. The value null is considered to be less than any other cookie and it is used for the first pull when no cookie has been set.

The order is the natural order of numbers and strings. If one of the cookies is an object then the value of the order property is treated as the cookie when doing comparison.

If one of the cookies is a string and the other is a number, the number is fist converted to a string (using toString()).

---

CreateIndexDefinition

Ƭ CreateIndexDefinition: IndexDefinition & { name: string }

---

CreateKVStore

Ƭ CreateKVStore: (name: string) => KVStore

Type declaration

▸ (name): KVStore

Factory function for creating KVStore instances.

The name is used to identify the store. If the same name is used for multiple stores, they should share the same data. It is also desirable to have these stores share an RWLock.

Parameters

Name	Type
name	string

Returns

KVStore

---

DeepReadonly

Ƭ DeepReadonly<T>: T extends null | boolean | string | number | undefined ? T : DeepReadonlyObject<T>

Basic deep readonly type. It works for JSONValue.

Type parameters

Name
T

---

DeepReadonlyObject

Ƭ DeepReadonlyObject<T>: { readonly [K in keyof T]: DeepReadonly<T[K]> }

Type parameters

Name
T

---

DropDatabaseOptions

Ƭ DropDatabaseOptions: Object

Options for dropDatabase and dropAllDatabases.

Type declaration

Name	Type	Description
kvStore?	"idb" | "mem" | KVStoreProvider	Allows providing a custom implementation of the underlying storage layer. Default is 'idb'.
logLevel?	LogLevel	Determines how much logging to do. When this is set to 'debug', Replicache will also log 'info' and 'error' messages. When set to 'info' we log 'info' and 'error' but not 'debug'. When set to 'error' we only log 'error' messages. Default is 'info'.
logSinks?	LogSink[]	Enables custom handling of logs. By default logs are logged to the console. If you would like logs to be sent elsewhere (e.g. to a cloud logging service like DataDog) you can provide an array of LogSinks. Logs at or above logLevel are sent to each of these LogSinks. If you would still like logs to go to the console, include consoleLogSink in the array. ts logSinks: [consoleLogSink, myCloudLogSink], Default is [consoleLogSink].

---

DropKVStore

Ƭ DropKVStore: (name: string) => Promise<void>

Type declaration

▸ (name): Promise<void>

Function for deleting KVStore instances.

The name is used to identify the store. If the same name is used for multiple stores, they should share the same data.

Parameters

Name	Type
name	string

Returns

Promise<void>

---

ExperimentalDiff

Ƭ ExperimentalDiff: ExperimentalIndexDiff | ExperimentalNoIndexDiff

Describes the changes that happened to Replicache after a WriteTransaction was committed.

This type is experimental and may change in the future.

---

ExperimentalDiffOperation

Ƭ ExperimentalDiffOperation<Key>: ExperimentalDiffOperationAdd<Key> | ExperimentalDiffOperationDel<Key> | ExperimentalDiffOperationChange<Key>

The individual parts describing the changes that happened to the Replicache data. There are three different kinds of operations:

• add: A new entry was added.

• del: An entry was deleted.

• change: An entry was changed.

  This type is experimental and may change in the future.

Type parameters

Name
Key

---

ExperimentalDiffOperationAdd

Ƭ ExperimentalDiffOperationAdd<Key, Value>: Object

Type parameters

Name	Type
Key	Key
Value	ReadonlyJSONValue

Type declaration

Name	Type
key	Key
newValue	Value
op	"add"

---

ExperimentalDiffOperationChange

Ƭ ExperimentalDiffOperationChange<Key, Value>: Object

Type parameters

Name	Type
Key	Key
Value	ReadonlyJSONValue

Type declaration

Name	Type
key	Key
newValue	Value
oldValue	Value
op	"change"

---

ExperimentalDiffOperationDel

Ƭ ExperimentalDiffOperationDel<Key, Value>: Object

Type parameters

Name	Type
Key	Key
Value	ReadonlyJSONValue

Type declaration

Name	Type
key	Key
oldValue	Value
op	"del"

---

ExperimentalIndexDiff

Ƭ ExperimentalIndexDiff: readonly ExperimentalDiffOperation<IndexKey>[]

This type is experimental and may change in the future.

---

ExperimentalNoIndexDiff

Ƭ ExperimentalNoIndexDiff: readonly ExperimentalDiffOperation<string>[]

This type is experimental and may change in the future.

---

ExperimentalWatchCallbackForOptions

Ƭ ExperimentalWatchCallbackForOptions<Options>: Options extends ExperimentalWatchIndexOptions ? ExperimentalWatchIndexCallback : ExperimentalWatchNoIndexCallback

Type parameters

Name	Type
Options	extends ExperimentalWatchOptions

---

ExperimentalWatchIndexCallback

Ƭ ExperimentalWatchIndexCallback: (diff: ExperimentalIndexDiff) => void

Type declaration

▸ (diff): void

Function that gets passed into experimentalWatch when doing a watch on a secondary index map and gets called when the data in Replicache changes.

This type is experimental and may change in the future.

Parameters

Name	Type
diff	ExperimentalIndexDiff

Returns

void

---

ExperimentalWatchIndexOptions

Ƭ ExperimentalWatchIndexOptions: ExperimentalWatchNoIndexOptions & { indexName: string }

Options object passed to experimentalWatch. This is for an index watch.

---

ExperimentalWatchNoIndexCallback

Ƭ ExperimentalWatchNoIndexCallback: (diff: ExperimentalNoIndexDiff) => void

Type declaration

▸ (diff): void

Function that gets passed into experimentalWatch and gets called when the data in Replicache changes.

This type is experimental and may change in the future.

Parameters

Name	Type
diff	ExperimentalNoIndexDiff

Returns

void

---

ExperimentalWatchNoIndexOptions

Ƭ ExperimentalWatchNoIndexOptions: Object

Options object passed to experimentalWatch. This is for a non index watch.

Type declaration

Name	Type	Description
initialValuesInFirstDiff?	boolean	When this is set to true (default is false), the watch callback will be called once asynchronously when watch is called. The arguments in that case is a diff where we consider all the existing values in Replicache as being added.
prefix?	string	When provided, the watch is limited to changes where the key starts with prefix.

---

ExperimentalWatchOptions

Ƭ ExperimentalWatchOptions: ExperimentalWatchIndexOptions | ExperimentalWatchNoIndexOptions

Options for experimentalWatch.

This interface is experimental and may change in the future.

---

GetIndexScanIterator

Ƭ GetIndexScanIterator: (indexName: string, fromSecondaryKey: string, fromPrimaryKey: string | undefined) => IterableUnion<readonly [key: IndexKey, value: ReadonlyJSONValue]>

Type declaration

▸ (indexName, fromSecondaryKey, fromPrimaryKey): IterableUnion<readonly [key: IndexKey, value: ReadonlyJSONValue]>

When using makeScanResult this is the type used for the function called when doing a scan with an indexName.

Parameters

Name	Type	Description
indexName	string	The name of the index we are scanning over.
fromSecondaryKey	string	The fromSecondaryKey is computed by scan and is the secondary key of the first entry to return in the iterator. It is based on prefix and start.key of the ScanIndexOptions.
fromPrimaryKey	string | undefined	The fromPrimaryKey is computed by scan and is the primary key of the first entry to return in the iterator. It is based on prefix and start.key of the ScanIndexOptions.

Returns

IterableUnion<readonly [key: IndexKey, value: ReadonlyJSONValue]>

---

GetScanIterator

Ƭ GetScanIterator: (fromKey: string) => IterableUnion<Entry<ReadonlyJSONValue>>

Type declaration

▸ (fromKey): IterableUnion<Entry<ReadonlyJSONValue>>

This is called when doing a scan without an indexName.

Parameters

Name	Type	Description
fromKey	string	The fromKey is computed by scan and is the key of the first entry to return in the iterator. It is based on prefix and start.key of the ScanNoIndexOptions.

Returns

IterableUnion<Entry<ReadonlyJSONValue>>

---

HTTPRequestInfo

Ƭ HTTPRequestInfo: Object

Type declaration

Name	Type
errorMessage	string
httpStatusCode	number

---

IndexDefinition

Ƭ IndexDefinition: Object

The definition of a single index.

Type declaration

Name	Type	Description
allowEmpty?	boolean	If true, indexing empty values will not emit a warning. Defaults to false.
jsonPointer	string	A JSON Pointer pointing at the sub value inside each value to index over. For example, one might index over users' ages like so: {prefix: '/user/', jsonPointer: '/age'}
prefix?	string	The prefix, if any, to limit the index over. If not provided the values of all keys are indexed.

---

IndexDefinitions

Ƭ IndexDefinitions: Object

An object as a map defining the indexes. The keys are the index names and the values are the index definitions.

Index signature

▪ [name: string]: IndexDefinition

---

IndexKey

Ƭ IndexKey: readonly [secondary: string, primary: string]

When using indexes the key is a tuple of the secondary key and the primary key.

---

IterableUnion

Ƭ IterableUnion<T>: AsyncIterable<T> | Iterable<T>

Type parameters

Name
T

---

JSONObject

Ƭ JSONObject: Object

A JSON object. This is a map from strings to JSON values or undefined. We allow undefined values as a convenience... but beware that the undefined values do not round trip to the server. For example:

// Time t1
await tx.set('a', {a: undefined});

// time passes, in a new transaction
const v = await tx.get('a');
console.log(v); // either {a: undefined} or {}

Index signature

▪ [key: string]: JSONValue | undefined

---

JSONValue

Ƭ JSONValue: null | string | boolean | number | JSONValue[] | JSONObject

The values that can be represented in JSON

---

KVStoreProvider

Ƭ KVStoreProvider: Object

Provider for creating and deleting KVStore instances.

Type declaration

Name	Type
create	CreateKVStore
drop	DropKVStore

---

KeyTypeForScanOptions

Ƭ KeyTypeForScanOptions<O>: O extends ScanIndexOptions ? IndexKey : string

If the options contains an indexName then the key type is a tuple of secondary and primary.

Type parameters

Name	Type
O	extends ScanOptions

---

LogLevel

Ƭ LogLevel: "error" | "warn" | "info" | "debug"

The different log levels. This is used to determine how much logging to do. 'error' > 'info' > 'debug'... meaning 'error' has highest priority and 'debug' lowest.

---

MakeMutator

Ƭ MakeMutator<F>: F extends (tx: WriteTransaction, ...args: infer Args) => infer Ret ? (...args: Args) => ToPromise<Ret> : never

Type parameters

Name	Type
F	extends (tx: WriteTransaction, ...args: [] | [ReadonlyJSONValue]) => MutatorReturn

---

MakeMutators

Ƭ MakeMutators<T>: { readonly [P in keyof T]: MakeMutator<T[P]> }

Type parameters

Name	Type
T	extends MutatorDefs

---

MaybePromise

Ƭ MaybePromise<T>: T | Promise<T>

Type parameters

Name
T

---

MutationV0

Ƭ MutationV0: Object

Mutation describes a single mutation done on the client. This is the legacy version (V0) and it is used when recovering mutations from old clients.

Type declaration

Name	Type
args	ReadonlyJSONValue
id	number
name	string
timestamp	number

---

MutationV1

Ƭ MutationV1: Object

Mutation describes a single mutation done on the client.

Type declaration

Name	Type
args	ReadonlyJSONValue
clientID	ClientID
id	number
name	string
timestamp	number

---

MutatorDefs

Ƭ MutatorDefs: Object

Index signature

▪ [key: string]: (tx: WriteTransaction, args?: any) => MutatorReturn

---

MutatorReturn

Ƭ MutatorReturn<T>: MaybePromise<T | void>

Type parameters

Name	Type
T	extends ReadonlyJSONValue = ReadonlyJSONValue

---

PatchOperation

Ƭ PatchOperation: { key: string ; op: "put" ; value: ReadonlyJSONValue } | { key: string ; op: "del" } | { op: "clear" }

This type describes the patch field in a PullResponse and it is used to describe how to update the Replicache key-value store.

---

PendingMutation

Ƭ PendingMutation: Object

Type declaration

Name	Type
args	ReadonlyJSONValue
clientID	ClientID
id	number
name	string

---

Poke

Ƭ Poke: Object

Type declaration

Name	Type
baseCookie	ReadonlyJSONValue
pullResponse	PullResponseV1

---

PullRequest

Ƭ PullRequest: PullRequestV1 | PullRequestV0

The JSON value used as the body when doing a POST to the pull endpoint.

---

PullRequestV0

Ƭ PullRequestV0: Object

The JSON value used as the body when doing a POST to the pull endpoint. This is the legacy version (V0) and it is still used when recovering mutations from old clients.

Type declaration

Name	Type
clientID	ClientID
cookie	ReadonlyJSONValue
lastMutationID	number
profileID	string
pullVersion	0
schemaVersion	string

---

PullRequestV1

Ƭ PullRequestV1: Object

The JSON value used as the body when doing a POST to the pull endpoint.

Type declaration

Name	Type
clientGroupID	ClientGroupID
cookie	Cookie
profileID	string
pullVersion	1
schemaVersion	string

---

PullResponse

Ƭ PullResponse: PullResponseV1 | PullResponseV0

---

PullResponseOKV0

Ƭ PullResponseOKV0: Object

The shape of a pull response under normal circumstances.

Type declaration

Name	Type
cookie?	ReadonlyJSONValue
lastMutationID	number
patch	PatchOperation[]

---

PullResponseOKV1

Ƭ PullResponseOKV1: Object

The shape of a pull response under normal circumstances.

Type declaration

Name	Type
cookie	Cookie
lastMutationIDChanges	Record<ClientID, number>
patch	PatchOperation[]

---

PullResponseV0

Ƭ PullResponseV0: PullResponseOKV0 | ClientStateNotFoundResponse | VersionNotSupportedResponse

PullResponse defines the shape and type of the response of a pull. This is the JSON you should return from your pull server endpoint.

---

PullResponseV1

Ƭ PullResponseV1: PullResponseOKV1 | ClientStateNotFoundResponse | VersionNotSupportedResponse

PullResponse defines the shape and type of the response of a pull. This is the JSON you should return from your pull server endpoint.

---

Puller

Ƭ Puller: (requestBody: PullRequest, requestID: string) => Promise<PullerResult>

Type declaration

▸ (requestBody, requestID): Promise<PullerResult>

Puller is the function type used to do the fetch part of a pull.

Puller needs to support dealing with pull request of version 0 and 1. Version 0 is used when doing mutation recovery of old clients. If a PullRequestV1 is passed in the n a PullerResultV1 should be returned. We do a runtime assert to make this is the case.

If you do not support old clients you can just throw if pullVersion is 0,

Parameters

Name	Type
requestBody	PullRequest
requestID	string

Returns

Promise<PullerResult>

---

PullerResult

Ƭ PullerResult: PullerResultV1 | PullerResultV0

---

PullerResultV0

Ƭ PullerResultV0: Object

Type declaration

Name	Type
httpRequestInfo	HTTPRequestInfo
response?	PullResponseV0

---

PullerResultV1

Ƭ PullerResultV1: Object

Type declaration

Name	Type
httpRequestInfo	HTTPRequestInfo
response?	PullResponseV1

---

PushRequest

Ƭ PushRequest: PushRequestV0 | PushRequestV1

---

PushRequestV0

Ƭ PushRequestV0: Object

The JSON value used as the body when doing a POST to the push endpoint. This is the legacy version (V0) and it is still used when recovering mutations from old clients.

Type declaration

Name	Type	Description
clientID	ClientID	-
mutations	MutationV0[]	-
profileID	string	-
pushVersion	0	-
schemaVersion	string	schemaVersion can optionally be used to specify to the push endpoint version information about the mutators the app is using (e.g., format of mutator args).

---

PushRequestV1

Ƭ PushRequestV1: Object

The JSON value used as the body when doing a POST to the push endpoint.

Type declaration

Name	Type	Description
clientGroupID	ClientGroupID	-
mutations	MutationV1[]	-
profileID	string	-
pushVersion	1	-
schemaVersion	string	schemaVersion can optionally be used to specify to the push endpoint version information about the mutators the app is using (e.g., format of mutator args).

---

PushResponse

Ƭ PushResponse: ClientStateNotFoundResponse | VersionNotSupportedResponse

The response from a push can contain information about error conditions.

---

Pusher

Ƭ Pusher: (requestBody: PushRequest, requestID: string) => Promise<PusherResult>

Type declaration

▸ (requestBody, requestID): Promise<PusherResult>

Pusher is the function type used to do the fetch part of a push. The request is a POST request where the body is JSON with the type PushRequest.

The return value should either be a HTTPRequestInfo or a PusherResult. The reason for the two different return types is that we didn't use to care about the response body of the push request. The default pusher implementation checks if the response body is JSON and if it matches the type PusherResponse. If it does, it is included in the return value.

Parameters

Name	Type
requestBody	PushRequest
requestID	string

Returns

Promise<PusherResult>

---

PusherResult

Ƭ PusherResult: Object

Type declaration

Name	Type
httpRequestInfo	HTTPRequestInfo
response?	PushResponse

---

ReadonlyJSONObject

Ƭ ReadonlyJSONObject: Object

Like JSONObject but deeply readonly

Index signature

▪ [key: string]: ReadonlyJSONValue | undefined

---

ReadonlyJSONValue

Ƭ ReadonlyJSONValue: null | string | boolean | number | ReadonlyArray<ReadonlyJSONValue> | ReadonlyJSONObject

Like JSONValue but deeply readonly

---

ScanIndexOptions

Ƭ ScanIndexOptions: Object

Options for scan when scanning over an index. When scanning over and index you need to provide the indexName and the start key is now a tuple consisting of secondary and primary key

Type declaration

Name	Type	Description
indexName	string	Do a scan over a named index. The indexName is the name of an index defined when creating the Replicache instance using indexes.
limit?	number	Only include up to limit results.
prefix?	string	Only include results starting with the secondary keys starting with prefix.
start?	{ exclusive?: boolean ; key: ScanOptionIndexedStartKey }	When provided the scan starts at this key.
start.exclusive?	boolean	Whether the key is exclusive or inclusive.
start.key	ScanOptionIndexedStartKey	-

---

ScanNoIndexOptions

Ƭ ScanNoIndexOptions: Object

Options for scan when scanning over the entire key space.

Type declaration

Name	Type	Description
limit?	number	Only include up to limit results.
prefix?	string	Only include keys starting with prefix.
start?	{ exclusive?: boolean ; key: string }	When provided the scan starts at this key.
start.exclusive?	boolean	Whether the key is exclusive or inclusive.
start.key	string	-

---

ScanOptionIndexedStartKey

Ƭ ScanOptionIndexedStartKey: readonly [secondary: string, primary?: string | undefined] | string

The key to start scanning at.

If you are scanning the primary index (i.e., you did not specify indexName), then pass a single string for this field, which is the key in the primary index to scan at.

If you are scanning a secondary index (i.e., you specified indexName), then use the tuple form. In that case, secondary is the secondary key to start scanning at, and primary (if any) is the primary key to start scanning at.

---

ScanOptions

Ƭ ScanOptions: ScanIndexOptions | ScanNoIndexOptions

Options for scan

---

TransactionEnvironment

Ƭ TransactionEnvironment: "client" | "server"

---

TransactionLocation

Ƭ TransactionLocation: TransactionEnvironment

---

TransactionReason

Ƭ TransactionReason: "initial" | "rebase" | "authoritative"

---

UpdateNeededReason

Ƭ UpdateNeededReason: { type: "NewClientGroup" } | { type: "VersionNotSupported" ; versionType?: "push" | "pull" | "schema" }

---

VersionNotSupportedResponse

Ƭ VersionNotSupportedResponse: Object

The server endpoint may respond with a VersionNotSupported error if it does not know how to handle the pullVersion, pushVersion or the schemaVersion.

Type declaration

Name	Type
error	"VersionNotSupported"
versionType?	"pull" | "push" | "schema"

Variables

TEST_LICENSE_KEY

• Const TEST_LICENSE_KEY: "This key only good for automated testing"

Deprecated

---

consoleLogSink

• Const consoleLogSink: LogSink

An implementation of [[LogSink]] that logs using console.log etc

---

version

• Const version: string

The current version of Replicache.

Functions

deleteAllReplicacheData

▸ deleteAllReplicacheData(opts?): Promise<{ dropped: string[] ; errors: unknown[] }>

Deletes all IndexedDB data associated with Replicache.

Returns an object with the names of the successfully dropped databases and any errors encountered while dropping.

Parameters

Name	Type
opts?	DropDatabaseOptions

Returns

Promise<{ dropped: string[] ; errors: unknown[] }>

Deprecated

Use dropAllDatabases instead.

---

dropAllDatabases

▸ dropAllDatabases(opts?): Promise<{ dropped: string[] ; errors: unknown[] }>

Deletes all IndexedDB data associated with Replicache.

Returns an object with the names of the successfully dropped databases and any errors encountered while dropping.

Parameters

Name	Type
opts?	DropDatabaseOptions

Returns

Promise<{ dropped: string[] ; errors: unknown[] }>

---

dropDatabase

▸ dropDatabase(dbName, opts?): Promise<void>

Deletes a single Replicache database.

Parameters

Name	Type
dbName	string
opts?	DropDatabaseOptions

Returns

Promise<void>

---

filterAsyncIterable

▸ filterAsyncIterable<V>(iter, predicate): AsyncIterable<V>

Filters an async iterable.

This utility function is provided because it is useful when using makeScanResult. It can be used to filter out tombstones (delete entries) for example.

Type parameters

Name
V

Parameters

Name	Type
iter	IterableUnion<V>
predicate	(v: V) => boolean

Returns

AsyncIterable<V>

---

getDefaultPuller

▸ getDefaultPuller(rep): Puller

This creates a default puller which uses HTTP POST to send the pull request.

Parameters

Name	Type
rep	Object
rep.auth	string
rep.pullURL	string

Returns

Puller

---

isScanIndexOptions

▸ isScanIndexOptions(options): options is ScanIndexOptions

Type narrowing of ScanOptions.

Parameters

Name	Type
options	ScanOptions

Returns

options is ScanIndexOptions

---

makeIDBName

▸ makeIDBName(name, schemaVersion?): string

Returns the name of the IDB database that will be used for a particular Replicache instance.

Parameters

Name	Type	Description
name	string	The name of the Replicache instance (i.e., the name field of ReplicacheOptions).
schemaVersion?	string	The schema version of the database (i.e., the schemaVersion field of ReplicacheOptions).

Returns

string

---

makeScanResult

▸ makeScanResult<Options>(options, getScanIterator): ScanResult<KeyTypeForScanOptions<Options>, ReadonlyJSONValue>

A helper function that makes it easier to implement scan with a custom backend.

If you are implementing a custom backend and have an in memory pending async iterable we provide two helper functions to make it easier to merge these together. mergeAsyncIterables and filterAsyncIterable.

For example:

const scanResult = makeScanResult(
  options,
  options.indexName
    ? () => {
        throw Error('not implemented');
      }
    : fromKey => {
        const persisted: AsyncIterable<Entry<ReadonlyJSONValue>> = ...;
        const pending: AsyncIterable<Entry<ReadonlyJSONValue | undefined>> = ...;
        const iter = await mergeAsyncIterables(persisted, pending);
        const filteredIter = await filterAsyncIterable(
          iter,
          entry => entry[1] !== undefined,
        );
        return filteredIter;
      },
);

Type parameters

Name	Type
Options	extends ScanOptions

Parameters

Name	Type
options	Options
getScanIterator	Options extends ScanIndexOptions ? GetIndexScanIterator : GetScanIterator

Returns

ScanResult<KeyTypeForScanOptions<Options>, ReadonlyJSONValue>

---

mergeAsyncIterables

▸ mergeAsyncIterables<A, B>(iterableBase, iterableOverlay, compare): AsyncIterable<A | B>

Merges an iterable on to another iterable.

The two iterables need to be ordered and the compare function is used to compare two different elements.

If two elements are equal (compare returns 0) then the element from the second iterable is picked.

This utility function is provided because it is useful when using makeScanResult. It can be used to merge an in memory pending async iterable on to a persistent async iterable for example.

Type parameters

Name
A
B

Parameters

Name	Type
iterableBase	IterableUnion<A>
iterableOverlay	IterableUnion<B>
compare	(a: A, b: B) => number

Returns

AsyncIterable<A | B>